It may not be the luxury auto brand's best-selling vehicle with the standard public, but the Mercedes-Benz B-Class F-Cell is proving quite popular with celebrities these days.  The hydrogen fuel cell EV is based on the traditional Mercedes-Benz B-Class, a small family car which has been sold in Europe and Canada since 2005 and is scheduled to finally make its full U.S. debut sometime this year. The first Mercedes-Benz F-Cell was based on the Mercedes-Benz A-Class and was released in 2002. Now, in 2012, the hydrogen EV is more advanced and more impressive than ever before.